I have lost two of my buttons I will no longer buy them or use themDS started using an MB at 8 without problems. We did peel the excess the shrink the band. The only problem we had was losing the magic bandits, the little button things. The sliders are fine though. You don't need anything to keep the bands on. They are really secure.
. I'm not saying that you NEED them, but I sure wish I had them. I know people say that losing a MB is not a big deal as you can get one replaced, but who wants to stand in a customer service line for X minutes on vacation if they don't have to. I'd suggest using the hair ties, or just getting the 10-pack of Bitbelts that way they are much cheaper. My wife uses one on her fitbit Charge and wouldn't go without it.